The present invention relates to an improved recorder, and more particularly relates to improvement in sound generating ability of a recorder provided with an attached sound collector.
The term "sound collector" used herein generally refers to a device which responds to vibration of a sound and generates a corresponding electric output signal, i.e. most typically a microphone.
In general, a conventional recorder takes the form of an elongated tube which is made up of a head joint, a middle joint and a foot joint coupled to each other at corresponding longitudinal ends.
The head joint includes a tubular main body and a fipple coupled to the upper end of the main body. A wind-way is formed through the fipple in communication with the bore of the main body. Near the lower end of the wind-way an open window is formed also in communication with the bore. Facing the lower end of the wind-way, a sharp edge projects into the window. With this construction, air blown out of the wind-way collides against the edge and a part of the air flows into the bore of the main body.
The middle joint has a bore open at both longitudinal ends and a plurality of aligned sound holes formed in communication with the bore. The foot joint also has a bore open in both longitudinal ends.
Air blown through the wind-way causes vibration of an air column whose length is determined by the distance between the window and the first open sound hole or holes. This vibration of the air column generates a corresponding musical tone which is emanated outwards through the window and the open sound hole or holes.
When a recorder is played within a small room, the audience can enjoy musical tones directly generated by the recorder. When performance is carried out in a large room or out doors, it is necessary to collect musical tones generated by the recorder by a proper sound collector, e.g. a microphone, and regenerate the tones using a sound system after proper amplification. For example, such a microphone is set at a prescribed distance from the recorder and sound waves from the window and the open sound hole or holes are collected by the microphone which amplifies the collected sound waves to form electric signals corresponding to the musical tones generated by the recorder. The electric signals are passed to a sound system for regeneration of corresponding amplified musical tones.
With such a system, there is no problem as long as the relative position between the recorder and the sound collector always remains unchanged. In practice, however, the player often moves the recorder in order to get in the swing of his performance. Such movement of the recorder changes the distance between the window of the recorder as well as the sound holes and the sound collector and, when repeated at random, the relative position between them fluctuates randomly. Such random fluctuation in relative position causes interference of sound waves from different sound holes of the recorder. The resulting change in sound collectng level at the sound collector seriously disturbs the correspondence in tone volume between the musical tones generated by the recorder and the musical tones regenerated by the sound system connected to the sound collector.
In addition, the damping of sound waves during transmission greatly lowers the sound pressure at the sound collector and amplification of the damped soundwaves makes the sound system extremely prone to howling.
Such troubles are basically caused by the fact that the sound collector is located a distance from the recorder. From this point of view, it is possible to mount a sound collector directly to the recorder itself. In practice, however, this expedient may be employed with a flute free of trouble but not with a recorder.
A flute generally takes the form of an elongated tube which is made up of a head joint, a middle joint and a foot joint connected to each other at their longitudinal ends. The top end of the head joint is plugged with a slidable reflector plate and a blow hole is formed at a position which is a prescribed distance from the reflector plate. The middle joint is provided with a plurality of aligned sound holes. With this construction, the capacity of a cavity left between the reflector and the blow hole is variable depending on the position of reflector plate and the effective length of the air column in the tube is defined by the distance between the reflector plate and the blow hole as reported by A. H. Benade et al in "Journal of Acoustical Society of America" Vol 37, P67.about.(1965). Due to this mechanism of sound vibration, the position of the reflector plate poses little influence on the tonal pitch of a sound to be generated. As a consequence, it is easy to arrange a sound collector in the above-described cavity of a flute.
In contrast, a recorder is not provided with such a cavity which has a small influence on tonal pitch. In the case of a recorder, the effective length of an air column is defined by the dimensions of the lower end of the fipple and the inner wall of the head joint. As a consequence, the configuration of the inner wall has a serious affect on the tonal pitch of a musical tone to be generated. Providing a sound collector internally of the recorder changes the original configuration of the inner wall and, as a consequence, tends to mar tonal quality of the musical tones to be generated.